<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        iframe {
            width: 500px;
            height: 300px;
            border: 2px solid #ccc;
        }
    </style>
</head>
<body>
    <a href="./红.html" target="main_frame">红</a>
    <a href="./绿.html" target="main_frame">绿</a>
    <a href="./蓝.html" target="main_frame">蓝</a>
    <hr>

    <!-- 利用iframe容器标签,来存放跳转的页面 -->
    <iframe src="./红.html" name="main_frame"></iframe>
</body>
</html>